Match values in 2 dataframes, NA error

It is necessary to use the data presented here, for the sake of the problem.
I would like to match values from 2 dataframes. however some values are not "matched", and I cannot see why!
I will try to concisely explain my problem.

2) dataframe with theoretical values

#2.1) the whole range of values that "Pos" can get
Source<- seq(0,17,0.01) #possible values that weight can get [0,17]
#2.2)height.0, the adjusted value of Height according to the Loop below
Table.match<- data.frame(Source=Source,Height.0=NA)
# loop for Source (real values)
for (i in 1:dim(Table.match)[1])
{
Table.match[i,"Height.0"] <- -57.5+5*(Table.match[i,"Source"])
}